Moa: extinct giant flightless birds of New Zealand

Biology and characteristics

Moa species varied greatly in size and build, from birds not much larger than a domestic turkey to giants with long necks and robust legs. They were herbivores, feeding on a range of leaves, twigs and other plant material. Anatomically, moas lacked wings suitable for flight and had strong legs adapted to walking. Paleontological studies, including analysis of preserved droppings and stomach contents (coprolites), have helped reconstruct their diet and the kinds of vegetation they browsed.

Species and size

Scientists recognize nine moa species across six genera. The largest and most famous belong to the genus Dinornis, which could reach heights reported up to 3.6 meters when the neck was extended and weighed several hundred kilograms. Smaller species occupied a range of ecological niches across the islands; some species were adapted to forested habitats while others lived in open country.

Human arrival and extinction

The Māori people, who migrated to New Zealand from parts of Oceania, brought new hunting pressures and ecological changes. Archaeological sites across the country show evidence of moa hunting and butchery. Combined effects of intensive hunting, habitat alteration and the later introduction of mammals led to moa extinction roughly within centuries after human arrival; surviving predators such as Haast's eagle had coexisted with moa but could not prevent their decline once humans impacted populations. Modern research also points to changes in habitat caused by human activity as a contributing factor.

Legacy and study

Moa have an outsized cultural and scientific importance. They provided food, tools and materials for the early Māori and figure in oral traditions. For scientists, moa remain the focus of ecological, genetic and conservation studies because their extinction illustrates the vulnerability of island ecosystems. Subfossil bones and other remains are recovered from caves, peat bogs and swamp deposits, aiding reconstruction of New Zealand's past environments.

Key points

• Endemic: moa lived only in New Zealand (see map).
• Diversity: nine species in six genera, from small to giant (species overview).
• Extinction causes: human hunting, habitat change and introduced animals are implicated (habitat change, introduced species).
• Predators: Haast's eagle preyed upon moa before humans arrived (predator-prey relations).